UBC Theses and Dissertations
Effects of Short Term Exposure to Suspended Sediment on the Behaviour of Juvenile Coho Salmon Berg, Linda
The territorial and feeding behaviour of juvenile coho salmon was studied in an artificial stream channel in response to short-term pulses of suspended sediment. Disruption of the social organization of the fish resulted at the higher turbidities tested. Dominance hierarchies were partially broken down, and territories were no longer defended. Only at lower turbidities were the hierarchies reformed and territories re-established. Behaviour following water clearance, closely resembled that observed prior to the addition of suspended sediment. The feeding behaviour of the fish was affected during the period of exposure to a pulse of suspended sediment. The ability of fish to capture prey items decreased with an increase in turbidity. The disruption of the social organization of the fish also caused modifications to their feeding behaviour. Rates of gill flaring increased in response to a pulse of suspended sediment and remained elevated following water clearance. Implications of these behavioural modifications are discussed in relation to fitness of fish populations rearing in streams subjected to frequent short-term pulses of suspended sediment.